Oshi-Tsubushi

is oshi-tsubushi, literally "squashing push", a Japanese term (also used in English, but in English it is called internal liberty shortage by Robert Jasiek) for a life and deathtesuji. The everyday translations, crush, squash, and smash, are also occasionally seen.

After , White's connection at the marked point is an illegal suicide move under most rulesets. Later Black can capture the two White stones, gaining two eyes and life.

Self-capture as ko threat

Under rulesets which allow self-capture, is possible; the three White stones are then immediately removed. If White can play at the point it would kill the black stones. now makes life, and so because Black must respond to attain it, the self-capturing move can be used as a ko threat.

Black instead tries to play ko and dies

If Black misses the oshi-tsubushi and instead takes the ko with , White plays under at and Black will die. Taking with is useless; White throws in with 4 at and Black only has a false eye here. (If instead of White mistakenly treats this as a ko fight, making a ko threat and then retaking the ko, Black gets a second chance at oshi-tsubushi.)

White to play and kill

If White to play in the original position, he can kill Black by connecting at and forming nakade. If captures the three stones, White 3 at holds Black to one eye.

Damezumari prevents oshi-tsubushi

Oshi-tsubushi can be prevented by damezumari. In this position, Black's lack of liberties means that after he is still in atari.